Temporal and Spatial Distribution of Different Grades of Precipitation Days in East China

The spatial and temporal distributions of rainy days with different precipitation intensities over East China were revealed using trend analysis, Mann-Kendall test, and EOF (Empirical Orthogonal Function) analysis methods on observed daily precipitation data for East China between 1961 and 2010. The results show that light precipitation rainy days made up 72.42% of the total number of rainy days, which was more than the other three precipitation grades. It was also evident that the number of light precipitation rainy days decreased and the total number of torrential and heavy precipitation days increased significantly over the study period. The EOF analysis results indicated that the two dominant EOF modes, number of light precipitation rainy days and total number of rainy days, decreased over the whole of East China and had opposite phases in northern and southern East China. The areas with the highest total numbers of rainy days and light precipitation days were in the middle of Fujian Province, where both parameters decreased the most. However, the areas with the highest numbers of torrential rain and heavy rain days were Zhejiang, Jiangxi, and Anhui provinces.